Single pole type recording head with tapered edges

ABSTRACT

A magnetic head for perpendicular recording without writing from the lateral sides of a main pole and without erasing data on adjacent tracks. A magnetic disk storage apparatus using the magnetic head. The lateral side of the main pole of a magnetic head for perpendicular recording may have an inverted tapered shape obtained by forming a groove as a track portion to an inorganic insulating layer and then forming a magnetic layer and then flattening the upper surface. A leading edge, a trailing edge, or both lateral edges of the magnetic head may be tapered. The taper may be either smooth and linear or curved in profile.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No. 10/768,104filed Feb. 2, 2004 and claims priority to U.S. application Ser. No.10/768,104 filed Feb. 2, 2004, which claims priority to Japanese PatentApplication Nos. 2000-286842 filed on Sep. 18, 2000 and 2000-328405filed on Oct. 23, 2000, all of which is incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention concerns a thin layer magnetic head used for recordingand reproduction, for example, in a magnetic disk storage apparatus anda magnetic disk storage apparatus mounting the magnetic head.

2. Description of the Background

In a magnetic disk storage apparatus, data on the recording media isread and written by a magnetic head. In order to increase the recordingcapacity per unit area of the magnetic disk, it is necessary to increasethe area recording density. However, the area recording density ofexisting in-plane recording systems can not be increased as the lengthof bits to be recorded is decreased because of thermal fluctuation inthe magnetization of the media.

A perpendicular recording system which records magnetization signals ina direction perpendicular to a medium is adapted to address thisproblem. In the perpendicular recording system, a magnetoresistive head(“MR head”) and a giant magnetoresistive head (“GMR head”) with a largerread output than non-perpendicular systems can be used for reading.However, a single pole head must to be used for the writing head inthese systems. With perpendicular recording, it may be necessary toimprove the track density and the linear recording density in order toimprove the recording density. To improve the track density, the trackwidth of the magnetic head is decreased and formed with higher accuracy.

In a perpendicular recording system, the shape of the main pole of thesingle pole type recording head has a significant effect on themagnetization pattern of the media. Specifically, the shape of the upperend face of the main pole, which is the end face of the main pole on theside opposite to the MR head (on the trailing side), greatly affects theshape of the magnetization pattern of the media. For example,JP-10-320720/1998 discloses the structure of a single pole type headhaving a main pole of a trapezoidal shape flattened at the upper endface and wider on the side of the MR head.

However, in the description in JP-10-320720/1998, a description is madeof side recording tracks defined by the slope on both sides of thetrapezoidal shape. These side recording tracks reduce cross talk withadjacent recording tracks, however, they hinder the improvement of thetrack density which therefore hinders any improvement in the arearecording density. In such a magnetic disk storage apparatus, a skewangle is formed when the magnetic head scans from the innercircumference to the outer circumference of a disk, in which thetrapezoidal pole shape erases signals on adjacent tracks.JP-10-320720/1998 has no specific descriptions about the pole formingmethod.

By using a polishing method, the upper surface of the main pole (secondpole) can be flattened. However, when a polishing method such aschemical mechanical polishing (CMP) is used, it is difficult to controlthe layer thickness which hinders the accuracy of the layer thickness.The thickness may vary by as much as about ±0.5 μm. This inaccuracyscatters the layer thickness of the main pole, thereby causingscattering in the intensity of the magnetic field from the main pole.Accordingly, it is preferred to adopt a flattening method for the uppersurface of the main pole having improved controllability (accuracy) forthe layer thickness.

In view of the above, the present invention preferably provides amagnetic head for perpendicular recording having a main pole of a shapewith no side recording which does not erase signals on adjacent trackscaused by a skew angle. The invention also includes a manufacturingmethod of the magnetic head and a magnetic disk storage apparatusmounting the magnetic head for perpendicular recording.

SUMMARY OF THE INVENTION

A single pole type recording head for perpendicular recording inaccordance with at least one preferred embodiment of the presentinvention comprises a first pole (auxiliary pole), a second pole (mainpole) and a gap layer formed between the first and second poles in whichthe width of the first pole opposed to the gap layer is larger than thewidth of the second pole opposed to the gap layer. When defining thesurface of the second pole opposed to the gap layer as a “lower layer”and the surface of the second pole on the side opposite the lowersurface (that is, on the trailing side) as an “upper surface” which isflat, the width (B) of the lower surface is preferably smaller than thewidth (A) of the upper surface in the second pole. Further, an angleformed between the upper surface and both lateral (side) surfaces of thesecond pole is an acute angle. In accordance with this invention, amagnetic disk storage apparatus is formed by mounting the magnetic head.

In at least one preferred embodiment, the second pole has a shape inwhich the size changes continuously (i.e., linearly) from the width forthe upper surface to the width for the lower surface of the second pole,and each lateral side of the second pole is desirably formed as a slope.In a preferred embodiment, the angle formed between the upper surfaceand both lateral sides to the upper surface of the second pole is withina range of approximately 60° to 90°. Further, the upper surface of thesecond pole may be characterized with a “flatness” that varies by lessthan about 30 nm between the end and the central portion in the uppersurface.

In accordance with this invention, a second pole (main pole) ispreferably formed by a process characterized by the following sequentialsteps: forming a resist pattern on an inorganic insulating layer;etching the inorganic insulating layer using the resist pattern as amask thereby forming a groove having a bottom surface larger than theupper surface and having a slope portion; removing the resist pattern;forming a magnetic layer on the inorganic insulating layer including thegroove; and flattening the magnetic layer. The second pole (main pole)may also be formed by a method, following the step of removing theresist pattern, including the sequential steps of: forming a stopperlayer for chemical mechanical polishing (CMP) on the inorganicinsulating layer; forming a plated underlayer on the stopper layer;plating a magnetic layer on the plated underlayer; and polishing themagnetic layer by chemical mechanical polishing (CMP).

Alternatively, the second pole (main pole) may also be formed by amethod, following the step of removing the resist pattern, including thesequential steps of: forming an etching stopper layer on the inorganicinsulating layer; forming a plated underlayer on the stopper layer;plating a magnetic layer on the plated underlayer; and flattening themagnetic layer by etching using plasmas.

The inorganic insulating layer is preferably a single layer comprisingAl₂O₃, AlN, SiC, Ta₂O₅, TiC, TiO₂ or SiO₂, or a laminate or mixed layercomprising two or more of the compounds described above. The magneticlayer constituting the second pole is preferably made of a materialhaving a saturation magnetic flux density (Bs) of at least 1.5 tesla(T). The stopper layer for chemical mechanical polishing (CMP) may be asingle layer comprising C, Ta, Mo, Nb, W or Cr, or a laminate layer oran alloy layer comprising the elements described above. The etchingstopper layer may be a single layer comprising Cr, Ni, Au, Pt, Pd, Ru,Rh, Cu, Ag, Tc, Re, Os or Ir or a laminate layer or an alloy layercomprising the elements described above.

In order to cope with a narrowed track of the recording head, the width(A) for the upper surface of the second pole (main pole) is preferably0.3 μm or less.

In the present invention, the second pole (main pole) of the magnetichead for perpendicular recording has a structure shape that canpreferably prevent writing to and erasing adjacent tracks caused by theskew angle in the lateral sides of the second pole. Initially, forpreventing writing from the lateral side of the second pole into theadjacent tracks, the shape of the second pole as viewed from themagnetic recording medium opposed surface (air bearing surface) may bean inverted tapered shape. It is also possible by forming the shape ofthe second pole in this way to prevent a portion of the second pole fromextending over the area of adjacent tracks and erasing the data on theadjacent tracks because of the skew angle.

The tapered angle of the inverted tapered shape depends on the skewangle, and the angle θ relative to the normal line direction to theupper surface of the second pole is preferably defined as 0°<θ<30°. Thatis, the angle between the upper surface and both of the lateral sides tothe upper surface of the second pole is preferably set within a range of60° to 90°. Further, the shape of the tapered portion is preferablychanged linearly from the width (A) for the upper surface to the width(B) for the lower surface.

Because the tapered angle thus formed may result in a lowering of themagnetic field intensity from the main pole, it may be necessary toincrease the saturation magnetic flux density (Bs) of the main pole toat least Bs=1.5 T (tesla). Materials to accomplish this may include, forexample, FeNi and CoNiFe.

As described above, both of the problems of writing into the sides anderasure of data on the adjacent tracks can be addressed by making theshape of the lateral sides of the main pole as viewed from the airbearing surface into an inverted tapered shape. Further, the uppersurface of the main pole can be provided with favorable controllabilityfor the layer thickness while flattening the upper surface bypreliminarily etching a groove into the inorganic insulating layer,forming a magnetic layer in the groove and then removing any unnecessaryportion by a polishing method or etching. For the inorganic insulatinglayer, a single layer comprising Al₂O₃, AlN, SiC, Ta₂O₅, TiC, TiO₂ orSiO₂, or a mixed or a laminate layer comprising the compounds as areknown in the art can be adopted.

The flatness for the surface of the main pole is preferably such that adifference in thickness (flatness or smoothness) between the end and thecentral portion of the main pole is no more than about 30 nm. Chemicalmechanical polishing (CMP) or a similar method can be used for thepolishing method, and the controllability of the layer thickness can beimproved by forming a stopper layer for CMP before polishing. As thestopper layer, a single layer comprising C, Ta, Mo, Nb, W or Cr or alaminate layer or an alloy layer comprising the element can be used.

When flattening is conducted by an etching method, the controllabilityof the layer thickness can be improved by forming an etching stopperlayer before etching. As the etching stopper layer, a single layercomprising Cr, Ni, Au, Pt, Pd, Ru, Rh, Cu, Ag, Tc, Re, Os or Ir, or alaminate layer or an alloy layer containing the element is preferred.Since the track width can be determined as the size of the resistpattern formed initially, the present method can preferably improve theaccuracy for the fabrication of the track width and may be particularlyeffective when a magnetic head with a track width of 0.3 μm or less isformed.

Fabricating the shape of the main pole in an inverse tapered shape asdescribed above may cause additional problems in the magnetic head. FIG.1A shows a schematic view of the magnetic head of one embodiment of theinvention, as viewed from the air bearing surface. In FIG. 1A, α is anangle formed between the oblique side of the trapezoidal main pole 1 andthe track running direction. When the shape of the air bearing surfaceof the main pole is made trapezoidal, the recording magnetic fielddensity is decreased. FIG. 1B shows the relationship between the maximummagnetic intensity of the main pole having a trapezoidal air bearingsurface and the angle α. It can be seen in FIG. 1B that the magneticfield intensity decreases as a increases.

Further, JP-12-76333/2000 describes a technique of preventing erasure ofdata on adjacent tracks by removing a portion of the magnetic pole ofthe writing head thereby reducing the extension of the magnetic pole tothe adjacent tracks. However, the magnetic field intensity of the headis also decreased in this case. Because the problem of thermalfluctuation becomes non-negligible as the size of the recording pitdecreases, the coercive force of the medium tends to be increased as acountermeasure for thermal fluctuation. Since the recording magneticfield of the head is required to have a sufficient size to be capable ofconducting recording to the medium, a decrease in the recording magneticfield intensity is disadvantageous to any improvement of the arearecording density.

The erasure of data on adjacent tracks caused by the skew angle may beaddressed without decreasing the recording magnetic field intensity byshaping the single pole type recording head so as to have a slope at theupper end of the main pole. In the single pole type recording headaccording to the present invention, the surface of the main polesituated “upstream” in the rotational direction of a recording mediumopposed by the writing head, (that is, on the leading side) is slantedrelative to the air bearing surface of the main pole. In other words, atapered surface is formed at the upper end of the main pole. When thetapered surface is formed as described above, the magnetic recordingintensity generated may be increased when compared with a similar devicewithout such a taper.

In addition to the increase in the recording magnetic field, thegenerated recording magnetic field can be concentrated or focused byoptimizing the slant of the tapered surface to the air bearing surfaceof the main pole. Specifically, the angle of the tapered surfacerelative to the main pole air bearing surface (hereinafter referred toas “the angle at the upper end of the main pole”) is defined as between45° and 75°. The tapered surface may also be disposed on the trailingside instead of the leading side of the main pole. Further, the taperedsurface may be disposed on both the trailing side and the leading side.

Manufacturing methods for the main pole having a tapered surface includeat least the following three methods. A first manufacturing methodpreferably comprises the following successive steps: forming a resistpattern on an inorganic insulating layer; etching the inorganicinsulating layer using the resist pattern as a mask thereby forming aslope; removing the resist pattern; forming a resist pattern on theinorganic insulating layer; forming a magnetic layer on the inorganicinsulating layer; removing the resist pattern; and a step of polishingto flatten the magnetic layer. A polishing method such as chemicalmechanical polishing or other appropriate methods may be used.

A second manufacturing method preferably includes the sequential stepsof: forming a tapered surface by a so-called lift off method whichcomprises forming a resist pattern on an inorganic insulating layer,sputtering the inorganic insulating layer and removing the resistpattern, the inorganic insulating layer deposited thereto therebyforming a slope; forming a resist pattern on the inorganic insulatinglayer forming; a magnetic layer on the inorganic insulating layer;removing the resist pattern; and polishing to flatten the magneticlayer.

A third manufacturing method preferably comprises the steps of forming aresist pattern on a magnetic layer and then etching the magnetic layerusing the resist pattern as a mask to thereby form a slope.

By manufacturing the main pole as described above, it may be possible toprovide a single magnetic pole type recording head that does not erasedata on adjacent tracks, while preventing a decrease in the magneticfield intensity. Further, it may be possible to provide a magneticrecording apparatus with a higher area recording density that issuperior in thermal fluctuation resistance to conventional apparatuses.This apparatus may be used in a longitudinal recording system bymounting a double layered perpendicular medium having a soft magneticunderlayer and a single pole type recording head.

BRIEF DESCRIPTION OF THE DRAWINGS

For the present invention to be clearly understood and readilypracticed, the present invention will be described in conjunction withthe following figures, wherein like reference characters designate thesame or similar elements, which figures are incorporated into andconstitute a part of the specification, wherein:

FIG. 1A is a schematic view of the shape of a main pole of an existingsingle pole type recording head, and FIG. 1B illustrates therelationship between the shape of the main pole and the perpendicularmagnetic field component of the head;

FIG. 2 is a schematic view of a magnetic disk storage apparatus in apreferred embodiment according to the present invention;

FIG. 3 is a schematic view of a magnetic disk storage apparatus in apreferred embodiment according to the present invention;

FIG. 4 illustrates the relationship between a magnetic head in apreferred and a magnetic disk;

FIG. 5 is a schematic view of a perpendicular recording apparatusaccording to the present invention;

FIG. 6 is a schematic view of a conventional magnetic head forperpendicular recording;

FIG. 7 is a schematic view of a magnetic head for perpendicularrecording according to the present invention;

FIG. 8 illustrates the relationship between a main pole of aconventional magnetic head for perpendicular recording and tracks on adisk;

FIG. 9 illustrates the relationship between a main pole of a magnetichead for perpendicular recording according to the present invention andtracks on a disk;

FIG. 10 is a schematic view of a conventional magnetic head;

FIG. 11 is a schematic view of a magnetic head for perpendicularrecording according to the present invention;

FIG. 12 is a schematic view of a process for forming a main poleaccording to the present invention;

FIG. 13 is a conceptual view of detailing the occurrence of the skewangle;

FIG. 14 is a schematic view showing the relationship between themagnetic head for perpendicular recording according to this inventionand a magnetic disk;

FIG. 15 is a schematic view showing the concept of perpendicularrecording;

FIG. 16 is a schematic view showing the shape of a main pole of a singlepole type recording head according to this invention;

FIG. 17 illustrates the relationship between the magnetic fieldintensity of a head and a top end angle of the single pole typerecording head and between the width of a magnetic field in therotational direction of a disk and the angle at the top end angle;

FIG. 18 shows a distribution of a magnetic field intensity in therunning direction of the disk of a single pole type recording headaccording to this invention;

FIG. 19 is a schematic view showing the shape of a main pole of a singlepole type recording head according to this invention;

FIG. 20 is a schematic view showing the shape of a main pole of a singlepole type recording head according to this invention;

FIG. 21 is a schematic view of a process for forming a main pole of asingle pole type recording head;

FIG. 22 is a schematic view of a process for forming a main pole of asingle pole type recording head;

FIG. 23 is a schematic view of a process for forming a main pole of asingle pole type recording head; and

FIG. 24 is a schematic view of a process for forming a main pole of asingle pole type recording head.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that the figures and descriptions of the presentinvention have been simplified to illustrate elements that are relevantfor a clear understanding of the invention, while eliminating, forpurposes of clarity, other elements that may be well known. Those ofordinary skill in the art will recognize that other elements aredesirable and/or required in order to implement the present invention.However, because such elements are well known in the art, and becausethey do not facilitate a better understanding of the present invention,a discussion of such elements is not provided herein. The detaileddescription will be provided hereinbelow with reference to the attacheddrawings.

First Exemplary Embodiment

FIG. 2 is a schematic view of a magnetic disk storage apparatusaccording to a preferred embodiment of the present inventionillustrating the relationship between a magnetic disk 7 and a magnetichead 10 (FIG. 2 is not to scale). The magnetic disk storage apparatushas a rotating magnetic disk 7 and a magnetic head 10 secured to one endof a support 9. The apparatus reads and writes magnetization signals 8on the magnetic disk 7. FIG. 3 is a schematic view when the magnetichead 10 is moved on the rotating magnetic disk 7 by swinging a support 9(not to scale). In this case, a skew angle β is formed between themagnetic head 20 supported by support 9 and a tangent drawn to a trackon the magnetic disk 7. The skew angle β changes as the head is rotatedacross various tracks (concentric circles on the disk 7) and istypically within a range of about ±30°.

FIG. 4 is a schematic view showing a magnetic head for perpendicularrecording according to a preferred embodiment of the present inventionand a magnetic disk (not to scale). Further, FIG. 5 is a schematic viewwhen perpendicular recording is conducted by using the magnetic head andthe magnetic disk shown in FIG. 4. A magnetic field 16 emitted from amain pole (second pole) 1 establishes a magnetic circuit passing througha recording layer 14 and a magnetic underlayer 15 as a soft magneticlayer that constitutes the magnetic disk 7. The magnetic field 16 thenenters an auxiliary pole (first pole) 11 to record a magnetizationpattern 13 in the recording layer 14. The auxiliary pole 11 also servesas an upper shield for the reproducing head.

In this case, the shape of a portion of the main pole 1 facing therecording layer 14 of the magnetic disk 7, that is, the air bearingsurface and the lateral side of the main pole 1 (the bottom or tip ofthe main pole 1 in FIGS. 4 and 5), has a significant effect on the shapeof the magnetization pattern depending on the disk rotation direction.FIG. 6 is a schematic view of a magnetic head having a main pole shapeas disclosed in JP-10-320720/1998.

Further, FIG. 8 shows a relation between adjacent tracks and the mainpole 17 when a skew angle is formed between the magnetic head shown inFIG. 6 and the disk track. A skew angle is formed in the main pole 17when the width of a lower surface 172 is larger than the width of anupper surface 171 and an angle formed between the upper surface 171 andthe lateral side 173 is an obtuse angle. This configuration results inthe lateral side 173 of the main pole 17 writing on the magnetizationsignals of an adjacent track (circled portion in FIG. 8). Since thewidth of the lateral side 173 is larger than the width of the uppersurface 171 of the main pole 17 that affects writing, the lateral side173 of the main pole 17 may extend so far on the area of the adjacenttrack as to conduct writing.

FIG. 7 shows a schematic view of a magnetic head according to thepresent invention as viewed from the air bearing surface. In the mainpole 1, the width is preferably at a maximum at the upper surface 121 ofthe main pole. Because the upper surface 121 of the main pole isadjusted with the track width of the recording head, the lateral side123 of the main pole 1 does not extend over the adjacent track as shownin FIG. 9. Accordingly, this constitution may be free from the problemof mistakenly writing magnetization signals on an adjacent track duringa writing operation.

As can be seen from FIG. 7 and FIG. 9, the tapered angle for the lateralside 123 of the main pole 1 is preferably determined depending on theskew angle. Accordingly, the tapered angle for the lateral side 123 ofthe main pole 1 is set depending on the constitution of the magneticdisk storage apparatus and an angle a relative to a normal linedirection for the upper surface 121 of the main pole 1 may be set withina range of approximately 0° to 30° (based on the skew angle describedabove). That is, the angle formed between the upper surface 121 and thelateral side 123 may be set within a range of approximately 60° to 90°.

FIG. 10 outlines a reading/writing separation type recording head. Ithas a structure in which a writing head is stacked on a reading headusing a magnetoresistive layer 5. FIG. 11 is a schematic view of areading/writing separation type recording head for perpendicularrecording in which the writing head and the reading head of the presentinvention are integrated.

One difference between these drawings is that the existing magnetic headincludes a thin gap layer 20 (for example, 0.2 μm) present at the mediumopposed surface (air bearing surface) between the upper magnetic core 22and an upper shield of a writing head that also serves as a lowermagnetic core 19 in the existing head. In the present invention (FIG.11), on the other hand, there is preferably a large space (for example 3to 5 μm) between the main pole 1 and the auxiliary pole 4.

Second Exemplary Embodiment

FIG. 12 is a schematic view for a presently preferred manufacturingmethod according to this invention (not to scale). FIG. 12A shows a stepof forming a resist pattern 24 on an inorganic insulating layer 23.Al₂O₃ may be preferred for the inorganic insulating layer, but SiC, AlN,Ta₂O₅, TiC, TiO₂, SiO₂ and other materials may also be used. The resistpattern 24 is exposed using a KrF excimer laser stepper. As the resist24, a positive resist such as TDUR-P201 manufactured by Tokyo Ohka KogyoCo., Ltd. may be used. When a resist of 0.7 μm thickness is formed, a0.2 μm size can be resolved.

FIG. 12B shows a, step of etching the inorganic insulating layer 23 byusing the resist 24 as a mask. When Al₂O₃ is used for the resist 24,BCl₃ or a gas mixture of BCl₃ and Cl₂ may be used as an etching gas. Inaddition, when AlN is used, the chlorine type gas described above ispreferred for etching. In a case where easily etchable Ta₂O₅, TiC, TiO₂,SiO₂, SiC and similar materials are used, fluorine gas such as CHF₃,CF₄, SF₆, C₄F₈ and similar etching gases can be used. The etching depthis preferably set to approximately 0.4 μm. The tapered angle in thisexemplary case for the inorganic insulating layer 23 is 10°.

FIG. 12C shows a step of removing the resist 24 after the etching. FIG.12D shows a step of forming a stopper layer 25 over the inorganicinsulation layer 23. When CMP is adopted for flattening in thesubsequent step, a stopper layer for CMP is formed, and an etchingstopper is formed in a case where the flattening process includesetching. In a case where the controllability for the layer thickness issatisfactory in the flattening step, the step of forming the stopperlayer may be omitted.

As the stopper layer for CMP, a single layer comprising C, Ta, Mo, Nb,W, Cr or similar material or an alloyed laminate layer can be used. Inone exemplary embodiment, sputtered C was used. Since C is chemicallystable, it is not polished chemically and, when it is mechanicallypolished, a polishing liquid waste is tinted black. Therefore, the endpoint of polishing is easily detected to improve the controllability forthe layer thickness of the main pole. As the etching stopper layer 25,noble metals not undergoing reactive etching may be used and a singlelayer comprising Au, Pt, Pd, Ru, Rh, Cu, Ag, Te, Re, Os, Ir or similarmaterials or a laminate or an alloy layer is preferred. In addition, Cr,Ni and others may also be used since they undergo no reactive etching.All of these layers may be formed by a sputtering method.

Thereafter, FIG. 12E shows a step of forming a magnetic layer 26. Thelayer 26 may be formed either by a plating method or a sputteringmethod. In the case of electrolytic plating, it may be necessary toapply plating after forming a plated underlayer. In a case of thesputtering method, since the groove formed in the steps of FIGS. 12B and12C has a large aspect ratio, it is necessary to use a method havingfavorable directionality, for example, a long throw sputtering orcollimation sputtering method, so as not to form voids in the magneticlayer. In a case of using the electrolytic plating method, Fe₅₅Ni₄₅having a saturation magnetic flux density of 1.6 T or CoNiFe having asaturation magnetic flux density of 1.9 T may be used. For the platedunderlayer, a magnetic layer of the same composition as that of theplated layer or a non-magnetic layer may be used.

FIG. 12F shows a step of flattening the upper surface of the magneticlayer 26 to form a main pole 1. For flattening, when a polishing methodsuch as CMP is used, the layer thickness can be controlled by stoppingthe polishing by the stopper layer 25, and the upper surface could beflattened completely. Flattening for less than 1 nm may be possible forthe entire groove as the track width. In an exemplary case, 0.2 μm ofthe track width identical with that of the resist pattern in the step ofFIG. 12A is obtained, and the tapered angle for the lateral side of themain pole was 10° (formed in the step of FIG. 12B.

Further, in a case of using etching for the flattening step, theflattening can be conducted by coating a resist a single time and thenconducting etching using a chlorine type gas, for example, BCl₃ or a gasmixture of BCl₃ and Cl₂ (so-called etching back). In this case, astopper layer 25 made of noble metals or a stopper layer made of Ni, Cror similar materials described above may be effective.

When the magnetic head for perpendicular recording according to thisexemplary embodiment is mounted, a magnetic disk storage apparatushaving an area recording density of at least 70 Gbit/in² may bemanufactured.

Third Exemplary Embodiment

FIG. 13 is an alternate schematic view of a medium-head system for amagnetic disk apparatus according to a preferred embodiment of thepresent invention (not to scale). As briefly described above, themagnetic disk storage apparatus writes and reads magnetization signalson a magnetic disk 7 using a magnetic head 28 attached to a slider 10fixed to one end of a suspension arm 9. The magnetic head 28 moves inthe radial direction of the disk 7 (seeking operation) by the swingingoperation of the suspension arm 9. Also as described above, a skew angleβ (of approximately ±30°) is set as shown in FIG. 13.

FIG. 14 is a schematic view for the relation between the writing/readinghead for perpendicular recording and a magnetic disk 7. Theperpendicular writing/reading head comprises a writing head part 30 anda reading head part 31. The writing head is a single pole type recordinghead and the reading head has a structure in which a reading device isdisposed between first and second soft magnetic shield layers. For thereading device, a giant magnetoresistive device (GMR element), tunnelmagnetoresistive device (TMR element) and other elements are usedbecause they are highly sensitive.

FIG. 15 shows a schematic view of a perpendicular writing/reading head.The magnetic field emitted from the main pole 1 of the single pole typerecording head establishes a magnetic circuit passing through therecording layer 14 and the magnetic underlayer 15, and entering theauxiliary magnetic pole 4 to record the magnetization pattern in therecording layer 14.

FIG. 16A shows a cross sectional view against the air bearing surface ofthe shape of the main pole 1 of the magnetic head according to thisinvention. FIG. 16B shows a schematic view for the main pole of themagnetic head as viewed from the air bearing surface. The main pole 1 onthe leading side 34 situated to the upstream in the disk rotationaldirection 2 is cut at the corner on the side of the air bearing surfaceof the main pole 1 to form an inclined shape (angle θ).

FIG. 17 shows the relationship between the upper end angle θ (leadingedge angle) and the maximum magnetic field intensity, and a relationbetween the half-value width in the disk rotational direction of therecording magnetic field distribution emitted from the main pole and thetop end angle θ. While the magnetic field intensity increases up toabout θ=45° and then decreases subsequently, a larger magnetic fieldintensity is obtained within a range of the top end angle θ from 0° toabout 75° compared with a state where the top end of the main pole isnot angled. Because this tends to concentrate on the magnetic fluxes onthe pole tip at the air bearing surface, this is considered to beattributable to the decrease in the amount of the magnetic fluxesflowing from the leading side (edge) of the main pole to the magneticmedium.

Further, in view of the relationship between the half-value width of therecording magnetic field distribution in the disk rotational directiongenerated from the main magnetic portion in FIG. 17 and the top endangle θ, it can be seen that the half-value width of the magnetic fieldin the disk rotational direction is decreased, (i.e., the recordingmagnetic field is further converged). This is considered to occurbecause the layer thickness 36 of the main pole 1 exposed to the airbearing surface is decreased by the provision of the tapered surface(based on θ). The half-value width decreases steeply up to about 45° ofthe top end angle θ and does not change significantly thereafter. Asdescribed above, for obtaining the converging effect for the recordingmagnetic field, it is effective to control the top end angle θ within arange of between approximately 45° and 75°.

FIG. 18 shows a recording magnetic flux distribution in the diskrotational direction 2 of the single pole type recording head accordingto the present invention and a conventional single pole type recordinghead where the top end angle θ is 0°. Compared with the conventionaldevice, FIG. 18 shows that the single pole type recording head accordingto this invention has a greater maximum magnetic field intensity and anarrower width of the recording magnetic field. In this case, themagnetic field gradient on the trailing side 33 that greatly effects therecording bit is not deteriorated. Accordingly, even when the skew angleis set, the recording width is not increased and erasure of data onadjacent tracks can be substantially prevented.

Fourth Exemplary Embodiment

While the tapered surface is provided on the leading side 34 of the topend of the main pole 1 in the third exemplary embodiment, the taperedsurface may also be disposed on the trailing side 33 of the main pole 1.FIG. 19A shows the shape of the single pole type recording head wherethe corner at the air bearing surface of the main pole 1 on the trailingside 33 situated downstream in the rotational direction 2 of the disk iscut into an inclined shape θ_(t). Also in this case, the width of themagnetic field in the disk rotational direction 2 can be narrowedwithout decreasing the magnetic field intensity, and the degree ofincrease of the recording width exceeding the geometrical track widthcan be suppressed. A magnetic head for perpendicular recording withouterasing data on adjacent tracks even though the existence of the skewangle may be provided according to this presently preferred exemplaryembodiment.

Fifth Exemplary Embodiment

In this embodiment, as shown in FIG. 19B, tapered surfaces are disposedon both of the leading side θ 34 and the trailing side θ_(t) 33 at thetop end of the main pole 1. The width of the magnetic field in the diskrotational direction 2 can be narrowed without decreasing the magneticfield intensity even when the corner at the air bearing surface of themain pole is cut into an inclined shape. Further, the degree of increaseof the recording width exceeding the geometrical track width can besuppressed, and a magnetic head for perpendicular recording withouterasing data on adjacent tracks even when the skew angle is set ispreferably provided.

Sixth Exemplary Embodiment

The sixth exemplary embodiment of the present invention preferablyincludes a case where the tapered surface formed at the top end of themain pole is a curved surface. While the tapered surface may be formedas a curved surface (not a planer or linear surface) depending on themanufacturing process, an identical effect can be obtained for thecurved tapered surface as in the planar tapered surface.

FIG. 20 is a cross sectional view in which the single pole typerecording head is viewed from the direction of the width of track. Thetapered surface disposed at the top end of the main pole 1 in this caseis a curved surface. In FIG. 20, the length indicated by h is aprojected length of the curved line formed by the curved tapered surfacerelative to the direction of the flying height and the length indicatedby W is a projected length of the curved line formed by the curvedtapered surface relative to the air bearing surface (when the top end ofthe main pole is viewed from the track direction as in FIG. 20).

Also in this case, as long as the angle θ defined as arc tangent forh/W, that is, θ=Arc Tan(h/W), is within a range between approximately45° and 75°, the same effect can be obtained as in a state where the topend angle θ is defined within a range between 45° and 75°.

Seventh Exemplary Embodiment

FIG. 21 and FIG. 22 show charts of a method for manufacturing a singlepole type recording head shown in the third exemplary embodiment. FIGS.21A and 22A show cross sectional views of the process, and FIGS. 21B and22B show views from the air bearing surface. To aid in understanding,the scale enlargement ratio for each portion in the drawing is notuniform.

Step (a) in FIG. 21 shows a state where a resist pattern 38 is formed onan inorganic insulating layer 39. A reading head part and an auxiliarypole layer 4 are formed below the inorganic insulating layer 39. For theinorganic insulating layer, SiC, AlN, Ta₂O₅, TiC, TiO₂ or SiO₂ may beused in addition to Al₂O₃ or other materials.

Step (b) in FIG. 21 shows a state where the inorganic insulating layer39 is etched using the resist pattern 38 as a mask. For the sake ofconvenience, the reading head portion and the auxiliary pole layer areomitted in the step (b) portion of FIG. 21 as well as in the subsequentdrawings. Since the portion at the resist end is hidden by the resist,it is etched less and the slope as shown in FIG. 21 is formed. As anetching gas, BCl₃ or a gas mixture of BCl₃ and Cl₂ may be suitable whenAl₂O₃ or AlN is used as the insulating layer 39. In a case where SiC,AlN, Ta₂O₅, TiC, TiO₂ and SiO₂ is used as the insulating layer 39,fluoric gas such as CHF₃, CF₄, SF₆ or C₄F₈ can be used since thematerial is easily etched.

Step (c) in FIG. 21 depicts a state where the resist is removed afteretching. Step (d) shows a state where a resist pattern 38 is formed.Step (e) of FIG. 22 shows a state where a magnetic layer 40 is plated.Fe₅₅Ni₄₅, CoNiFe and similar materials can be used as the material forthe magnetic layer 40 since they have high saturation magnetic fluxdensity and favorable soft magnetic characteristic. For the platedunderlayer, either a magnetic layer of an identical composition withthat of the plated layer or a non-magnetic layer may be used.

Step (f) in FIG. 22 shows a state where the resist 38 is removed. Step(g) shows a state where the air bearing surface 35 of the magnetic layer40 is flattened by polishing to form a main pole. A polishing methodsuch as chemical mechanical polishing (CMP) may be used for theflattening step. In the step for forming the air bearing surface, theair bearing surface 35 may be formed at a position shown by the dottedline. The single pole type recording head for perpendicular recordingaccording to this invention in which the tapered surfaces is formed onthe leading side may be manufactured by the manufacturing methoddescribed above.

Eighth Exemplary Embodiment

The FIG. 23 chart depicts another manufacturing method of a single poletype recording head according to this invention utilizing the lift-offsystem. Again, FIG. 23A shows a cross sectional view, and FIG. 23B showsa view from the air bearing surface. In the same manner as in FIGS.21-22, while the reading head portion and the auxiliary pole layer areformed below the inorganic insulating layer 39, they are omitted for thesake of convenience.

At first, a resist pattern 38 of a shape as shown in FIG. 23 is formedon an inorganic insulating layer 39. While soft magnetic layers for areading head and an auxiliary pole are formed below the inorganicinsulating layer 39, they are omitted in the drawing. Step (a) in FIG.23 shows a state where the resist pattern 38 is formed. Then, forforming the slope, sputtering is applied on the resist pattern 38 of theinorganic insulating layer 39. Step (b) shows a state where sputteringis applied. The angle of the slope can be controlled by adjusting thetarget-to-substrate distance upon sputtering, the gas pressure uponsputtering, the angle of the substrate relative to the target, and othercharacteristics of the sputtering method.

After sputtering, the resist 38 and the inorganic insulating layer 39deposited thereto are removed. Step (c) in FIG. 23 shows a state wherethe resist is removed. Step (d) shows a state where another resistpattern 38 is formed. Step (e) shows a state where a magnetic layer 40is plated. Step (f) shows a state where the resist 38 is removed, andstep (g) shows a state where the upper surface of the magnetic layer 40is flattened to form a main pole. In the step of forming the air bearingsurface, the air bearing surface 21 may be situated at a position shownby a dotted line in the drawing. A magnetic head for perpendicularrecording having a slope on the leading side may be produced by themanufacturing method described above.

Ninth Exemplary Embodiment

FIG. 24 is a step chart for an additional method of manufacturing asingle pole type recording head according to this invention. FIG. 24(a)shows a state where a resist pattern 38 of the shape shown in thedrawing is formed on an inorganic insulating layer 39 and a magneticlayer 40 laminated in this order as the main pole. FIG. 24(b) shows astate where the magnetic layer 40 is etched by using the resist pattern38 as a mask. FIG. 24(c) shows a state where a resist 38 is removedafter etching. In the step of forming an air bearing surface, the airbearing surface 35 may be situated at a position shown by a dotted linein FIG. 24(c). A magnetic head for perpendicular recording according tothis invention having a slope on the trailing side can be manufacturedby the manufacturing method described above.

It is possible to provide a magnetic head for perpendicular recordingcapable of suppressing the degree of increase in the recording width toless than the geometrical track width without decreasing the maximumrecording magnetic field intensity. Further, magnetic heads according tothe present invention preferably do not erase data on adjacent trackseven when the skew angle is set by shaping the main pole such that thetapered surface is provided to the top end on the leading side or thetrailing side. This head may mounting to form a magnetic storageapparatus.

The foregoing invention has been described in terms of preferredEmbodiments. However, those skilled, in the art will recognize that manyvariations of such Embodiments exist. Such variations are intended to bewithin the scope of the present invention and the appended claims.

Nothing in the above description is meant to limit the present inventionto any specific materials, geometry, or orientation of elements. Manypart/orientation substitutions are contemplated within the scope of thepresent invention and will be apparent to those skilled in the art. Theembodiments described herein were presented by way of example only andshould not be used to limit the scope of the invention.

Although the invention has been described in terms of particularembodiments in an application, one of ordinary skill in the art, inlight of the teachings herein, can generate additional embodiments andmodifications without departing from the spirit of, or exceeding thescope of, the claimed invention. Accordingly, it is understood that thedrawings and the descriptions herein are proffered by way of exampleonly to facilitate comprehension of the invention and should not beconstrued to limit the scope thereof.

1. A single pole type recording head for recording on a perpendicularmagnetic recording medium having a soft magnetic underlayer comprising:a main pole including an upper, lower, and two lateral side surfaces,and further including an air bearing surface which is generallyperpendicular to said upper and lower surfaces, said lower surface andupper surface defining a leading side and a trailing side of the mainpole, respectively; and an auxiliary pole, wherein said two lateral sidesurfaces of the main pole are tapered in the direction of the flyingheight as viewed from the air bearing surface, and further wherein saidmain pole is tapered on the trailing side in the direction of the flyingheight as viewed from the air bearing surface.
 2. A writing/reading headcomprising: a reading head; and a single pole type writing head forrecording on a perpendicular magnetic recording medium having a softmagnetic underlayer comprising a main pole including an upper, lower,and two lateral side surfaces, and further including an air bearingsurface which is generally perpendicular to said upper and lowersurfaces, said lower surface and upper surface defining a leading sideand a trailing side of the main pole, respectively, and an auxiliarypole, wherein said two lateral side surfaces of the main pole aretapered in the direction of the flying height as viewed from the airbearing surface, and further wherein said main pole has a taperedsurface on the trailing side in the direction of the flying height asviewed from an air bearing surface, further wherein the tapered surfaceintersects the air bearing surface.
 3. A writing/reading head accordingto claim 2, wherein the angle formed between the air bearing surface ofthe main pole and the tapered surface is no more than 75°.
 4. Awriting/reading head according to claim 3, wherein said angle is in therange of 45° to 75°.
 5. A writing/reading head, comprising: a readinghead; and a single pole type recording head comprising a main pole andan auxiliary pole, wherein the main pole has a tapered surface on thetrailing side in the direction of the flying height as viewed from anair bearing surface, and wherein the tapered surface intersecting theair bearing surface, and the angle θ defined as θ=Arc Tan(h/W) isbetween 45° and 75°, where h represents a projected length of a segmentformed with the tapered surface in the direction of the flying heightrelative to the cross section and W represents a projected length of thesegment to the air bearing surface of the main pole as viewed from thedirection of the track.
 6. A magnetic disk storage apparatus,comprising: a single pole type recording head for recording on aperpendicular magnetic recording medium having a soft magneticunderlayer having an auxiliary pole, and a main pole including an upper,lower, and two lateral side surfaces, and further including an airbearing surface which is generally perpendicular to said upper, lowerand two lateral side surfaces, said lower surface and upper surfacedefining a leading side and a trailing side of the main pole,respectively, wherein said two side surfaces of the main pole aretapered in the direction of the flying height as viewed from the airbearing surface, and further wherein said main pole tapered in thedirection of the flying height on the trailing side as viewed from theair bearing surface; and a perpendicular magnetic recording mediumhaving a soft magnetic underlayer, a magnetic circuit is establishedfrom the main pole through the magnetic underlayer and into theauxiliary magnetic pole.
 7. A magnetic disk storage apparatus accordingto claim 6, wherein the angle formed between the air bearing surface andthe tapered surface of the main pole is in the range the range ofapproximately 45° to 75°.
 8. A single pole type recording head accordingto claim 1, wherein a magnetic circuit is established from the main polethrough the magnetic underlayer and into the auxiliary magnetic pole. 9.A writing/reading head according to claim 2, wherein a magnetic circuitis established from the main pole through the magnetic underlayer andinto the auxiliary magnetic pole.
 10. A single pole type recording headaccording to claim 1, wherein the taper of said two side surfaces occursin two stages, wherein in an upper taper portion (away from said airbearing surface), the two side surfaces are tapered a first amount, andin a lower taper portion (between said upper taper portion and said airbearing surface, the two side surfaces are tapered substantially morethan said first amount.
 11. A writing/reading head according to claim 2,wherein the taper of said two side surfaces occurs in two stages,wherein in an upper taper portion (away from said air bearing surface),the two side surfaces are tapered a first amount, and in a lower taperportion (between said upper taper portion and said air bearing surface,the two side surfaces are tapered substantially more than said firstamount.